Bulletin  251 


December,  1923 


Co  MM 
S 


Connecticut 
Agricultural  Experiment  Station 


NEW  HAVEN,  CONN. 


The  Raspberry  Fruit  Worm 


By  B.  H.  WALDEN. 


i  v  - 


Figure  1.     Infested  Raspberry. 


CONTENTS. 


Page 
The  Raspberry  Fruit  Worm. . .     91 

History  and  Distribution 91 

Food  Plants  and  Injury 92 

Life  History  and  Habits 93 


Page 

Description 95 

Control  Methods 96 

General  Recommendations  ...     99 
Literature 99 


The  Bulletins  of  this  Station  are  mailed  free  to  citizens  (if  Connecticut 
who  apply  for  them,  and  to  other  applicants  as  far  as  the  editions  permit. 


CONNECTICUT  AGRICULTURAL  EXPERIMENT  STATION 

OFFICERS  AND  STAFF 
December,  1923. 


BOARD  OF  CONTROL. 

His  Excellency,  Charles  A.  Templeton,  ex-officio,  President. 

James  H.  Webb,  Vice-President Hamden 

George  A.  Hopson,  Secretary Mount  Carmel 

Wm.  L.  Slate,  Jr.,  Director  and  Treasurer New  Haven 

Joseph  W.  Alsop Avon 

Charles  R.  Treat Orange 

Elijah  Rogers Southington 

Edward  C.  Schneider Middletown 

STAFF. 
E.  H.  Jenkins,  Ph.D.,  Director  Emeritus. 


Administration. 


W.  L.  Slate,  Jr.,  B.Sc,  Director  and  Treasurer. 
Miss  L.  M.  Bhautlecht,  Bookkeeper  and  Librarian. 
Miss  J.  V.  Bergek,  Stenographer  and  Bookkeeper. 
Miss  Mary  Bradley,  Secretary. 
William  Veitch,  In  Charge  of  Buildings  and  Grounds. 


Chemistry. 

Analytical  Laboratory. 


E.  M.  Bailey,  Ph.D.,  Chemist  in  Charge. 

R.  E.  Andrew,  M.A. 

C.  E.  Shepard  I      .     . J     .    ' 

Owen  L.  Nolan  [    Assistant  Chemists. 

Harry  J.  Fisher,  A.B.     J 

Frank  Sheldon,  Laboratory  Assistant. 

V.  L.  Churchill,  Sampling  Agent. 

Miss  Mabel  Bacon,  Stenographer. 


Biochemical 
Laboratory. 

Botany. 


T.  B.  Osborne,  Ph.D.,  Sc.D.,  Chemist  in  Charge. 


G.  P.  Clinton,  Sc.D.,  Botanist  in  Charge. 

E.  M.  Stoddard,  B.S.,  Pomologist. 

Miss  Florence  A.  McCormick,  Ph.D.,  Pathologist. 

G.  E.  Graham,  General  Assistant. 

Mrs.  W.  W.  Kelsey,  Secretary. 


Entomology. 


W.  E.  Britton,  Ph.D., Entomologist  in  Charge;  Stale  Entomologist. 

B.  H.  Walden,  B.Agr.      1 

M.  P.  Zappe,  B.S.  )•   Assistant  Entomologists. 

Philip  Garman,  Ph.D.      J 

John  T.  Ashworth,  Deputy  in  Charge  of  Gipsy  Moth  Work. 

R.  C.  Botsford,  Deputy  in  Charge  of  Mosquito  Elimination. 

Miss  Gladys  M.  Finley,  Stenographer. 


Forestry. 


Walter  O.  Filley,  Forester  in  Charge. 
A.  E.  Moss,  M.F.,   Assistant  Forester. 
H.  W.  Hicock,  M.F.,  Assistant  Forester. 
Miss  Pauline  A.  Merchant,  Stenographer. 


Plant  Breeding. 


Donald  F.  Jones,  S.D.,  Geneticist  in  Charge. 
P.  C.  Mangelsdorf,  M.S.,  Assistant. 


Soil  Research. 


Tobacco  Sub-station 
at  Windsor. 


M.  F.  Morgan,  M.S.,  Investigator. 
C.  M.  Slagg,  M.S.,  in  Charge. 


The  Wilson  H.-  Lee  Co. 


The  Raspberry  Fruit  Worm. 

Byturus  unicolor  Say 
Br  B.  H.  Walden,  B.Agr. 

Though  the  Raspberry  Fruit  Worm  or  Raspberry  Beetle  has 
long  been  known  as  a  pest  of  red  raspberries  in  the  United  States, 
very  little  has  been  published  by  economic  entomologists  regard- 
ing its  life  history  or  habits. 

The  first  published  record  of  the  occurrence  of  this  species  in 
Connecticut  was  by  Lintner,6  State  Entomologist  of  New  York, 
to  whom  specimens  were  submitted  for  identification  from  North 
Haven,  May  25,  1891.  The  species  has  been  represented  in  our 
collection  since  1902.  although  few  complaints  of  injury  have  been 
received  until  within  the  last  three  or  four  years. 

The  insect  has  apparently  been  on  the  increase  in  the  State 
since  the  St.  Regis  everbearing  raspberries  came  into  general 
cultivation.  In  1920,  Mr.  George  Hunter,  a  grower  of  small 
fruits  in  East  Haven,  reported  that  his  St.  Regis  raspberries  were 
badly  infested  with  small,  whitish  worms  which  upon  investigation 
proved  to  be  the  larvae  of  Byturus  unicolor  Say.  From  1921  to 
1923  the  following  observations  on  the  nabits  and  life  history  of 
this  insect  were  largely  made  upon  his  grounds  in  East  Haven. 

History  and  Distribution. 

Byturus  unicolor  was  described  in  1823  by  Thomas  Say1  -oma 
single  specimen  collected  in  Arkansas.  It  was  mentioned  by 
Packard2  as  injuring  raspberries  at  Salem,  Massachusetts,  in  1869. 
The  most  complete  early  account  of  the  injury  and  habits  of  the 
species  observed  by  the  writer  was  pubhrhed  by  Fitch3  of  New 
York  in  1870-1872.  Saunders4  reported  injury  by  this  insect  in 
1873  without  mentioning  any  specific  locality,  but  his  observations 
were  undoubtedly  made  in  Ontario.  Fletcher5  records  the  species 
definitely  from  Ontario  in  1887.  Goodwin7  of  Ohio  published  in 
1909  additional  information  regarding  the  habits  and  hie  history, 
together  with  results  of  experiments  in  controlling  the  insect. 
Various  wiiters  have  recorded  the  species  from  many  parts  of  the 
United  States.  It  undoubtedly  occurs  throughout  the  southern 
part  of  Canada  and  the  United  States  with  the  exception  of  some 
of  the  more  southern  states.  Leng8  gives  its  range  from  the 
Atlantic  Coast  to  Washington  and  Arizona. 


92  CONNECTICUT   EXPERIMENT   STATION.  BULLETIN   251. 

Food  Plants  and  Injury. 

In  Connecticut  this  insect  has  been  found  attacking  the  fruit 
of  only  the  red  species  of  raspberries  and  it  shows  a  decided 
preference  for  certain  horticultural  varieties.  The  work  of  the 
adults,  however,  has  been  observed  on  the  foliage  of  black  cap 
raspberries  and  the  Columbian  or  purple  raspberry.  There  are 
also  two  records  in  the  notes  of  the  department  where  this  insect 
has  apparently  infested  the  fruit  of  blackberry.  Here  again  it 
seems  to  show  preference  for  certain  varieties  as  in  East  Haven, 
where  there  were  two  rows  of  blackberries  (variety  not  known) 
adjoining  the  experimental  plot  of  raspberries  and  no  injury  was 
observed  either  on  tie  foliage  or  to  the  fruit.  As  indicated  above, 
the  early  fruit  of  the  St.  Regis  variety  is  especially  subject  to 
attack.  A  small  block  of  the  Victory  raspberry  in  Montowese, 
the  only  planting  of  this  recent  variety  observed,  also  showed 
considerable  injury  by  this  beetle.  The  fruit  of  the  Cuthbert,  an 
old  standard  variety  which  is  considered  one  of  the  best  com- 
mercial varieties  of  the  state,  however,  has  not  been  found  seriously 
infested.  The  owner  of  the  Victory  raspberries  in  Montowese  has 
grown  the  Cuthbert  and  St.  Regis  side  by  side;  the  latter  was  so 
badly  infested  that  the  variety  was  discarded.  In  North  Branford 
where  the  two  varieties  were  grown  in  the  same  field  similar  con- 
ditions regarding  the  infestations  were  observed.  Goodwin,  in 
Ohio,  found  the  King  variety  severely  injured  while  the  fruit  of 
the  Cuthbert  was  scarcely  attacked,  and  gives  the  following  as  a 
possible  explanation:  "The  longer  and  more  open  bud  clusters 
of  the  Cuthberts,  affording  less  opportunity  for  the  beetles  to  feed 
conveniently,  seemed  to  be  the  only  reasonable  explanation  for 
the  comparative  immunity,  because  tie  tender  leaves  of  the 
latter  seemed  to  be  injured  fully  as  much  as  the  King." 

Dr.  Felt9  of  New  York  records  serious  injurv  to  the  Perfection 
variety  in  the  Hudson  Valley.  The  injury  was  much  greater  on 
an  exceptionally  early  patch  of  this  variety  than  on  one  wl  ere 
the  fruit  buds  developed  a  week  later,  and  he  states  that  "the 
relative  earlmess  of  the  field  may  be  an  important  factor  in  de- 
termining the  amount  of  injury." 

There  are  three  distinct  types  of  injury  caused  bv  the  insect. 

1.  The  adults  feed  on  the  unfolding  leaves,  often  skeletonizing 
them.     Plate  IV,  a. 

2.  As  the  blossom  buds  appear  the  beetles  attack  these,  eating 
out  the  inside  and  when  numerous  may  destroy  the  whole  bud 
cluster.     Plate  II,  a. 

3.  The  third  type  of  injury  is  caused  by  the  larvae  infesting 
the  fruit.  In  many  cases  the  larvae  develop  in  and  destroy  the 
fleshy  receptacle  on  which  the  fruit  is  borne,  causing  the  fruit  to 
dry  up  before  ripening,  or  they  may  feed  on  the  carpels  which 
dry  up  or  become  infected  with  a  mould  which  causes  the  re- 


THE    RASPBERRY    FRUIT    WORM.  93 

mainder  of  the  berry  to  decay  or  become  soft.  At  picking  time 
many  of  the  berries  which  do  not  show  any  exterior  injury  will 
each  be  found  to  contain  a  larva  which  has  worked  partly  on  the 
underside  of  the  fruit  and  partly  in  the  receptacle.  The  larvae 
frequently  adhere  to  the  picked  fruit,  and  even  with  careful 
sorting  it  is  hard  to  detect  all  of  them.     Plate  I,  c. 

In  the  East  Haven  field  in  1921,  a  count  of  the  fruit  buds  in  the 
most  severely  infested  portion  of. the  field  showed  that  about  37 
per  cent,  of  the  buds  had  been  injured  by  the  beetles  and  at  the 
time  the  fruit  was  ripening  57.9  per  cent,  of  the  berries  that  de- 
veloped were  infested  with  the  larvae.  The  owner  did  not  harvest 
the  early  fruit  of  this  variety  either  in  1921  or  1922. 

The  fall  fruit  is  not  attacked  by  this  insect. 

Life  History  and  Habits. 

The  beetles  appear  in  spring  soon  after  the  new  growth  of  the 
plants  is  well  started.  In  1921  they  were  abundant  on  May  10, 
at  the  time  of  the  first  visit  to  the  field.  In  1922  observations  were 
made  from  April  19,  and  the  first  adults  were  found  on  May  8 
and  were  appearing  in  numbers  from  May  12  to  May  16.  The 
beetles  seem  to  prefer  the  sunlight  and  are  found  on  the  tips  of 
the  plants  on  bright  sunny  days.  In  cold,  cloudy  weather  the 
beetles  are  inactive  and  seek  protection  under  the  foliage. 

They  feed  for  a  number  of  days  before  mating  and  laying  eggs. 
The  leaves  before  opening  are  folded  in  more  or  less  of  a  fan- 
shaped  manner  and  the  beetles  feed  along  the  upper  surface  of  the 
folds,  so  that  when  the  leaves  are  fully  open  they  are  perforated 
with  a  series  of  elongated  holes  which  parallel  the  veins.  When 
the  beetles  are  abundant  nearly  all  of  the  tissue  between  the  veins 
may  be  eaten  as  shown  on  Plate  IV,  a.  After  the  blossom  buds 
are  formed  the  beetles  attack  these,  eating  out  the  inside  as  shown 
on  Plate  III,  b. 

When  disturbed  the  beetles  will  fly  for  a  short  distance  but 
apparently  do  not  spread  rapidly  in  the  field.  The  insects  were 
more  abundant  towards  the  south  end  of  the  block  in  1921  and 
the  same  condition,  to  a  somewhat  less  extent,  was  true  in  1922. 
A  new  block  of  St.  Regis  raspberries  was  set  about  sixty  feet  from 
the  old  one  in  1921,  and  no  beetles  were  found  on  it  that  season. 
In  1922  only  five  or  six  adults  were  seen  on  the  new  plants  and  but 
a  very  few  larvae  were  found  in  the  fruit.  These  were  in  two 
rows  towards  the  old  field.  Low  growing  crops  were  planted  each 
year  on  the  intervening  space. 

By  June  5  the  majority  of  the  beetles  had  disappeared,  although 
a  few  remained  longer;  the  latest  date  that  a  beetle  was  observed 
in  the  field  was  on  June  22. 

The  first  eggs  were  found  on  May  22,  fourteen*  days  after  the 
first  adults  were  observed,  although  in   1921,  three  eggs  were 


94  CONNECTICUT   EXPERIMENT   STATION.  BULLETIN   251. 

found  on  May  10.  The  eggs  are  deposited  singly  and  are  quite 
difficult  to  find  in  the  field.  The  position  of  the  eggs  on  each  of  a 
number  of  tips  examined  at  about  the  time  the  first  blossom  buds 
opened  was  as  follows: 

On  base  of  blossom  buds 10 

In  cavity  eaten  in  buds 2 

On  bud  petioles 4 

Axil  of  bud  petioles 5 

Axil  of  bud  and  leaf  petioles 2 

Axil  of  leaflet  petioles 4 

Underside  of  leaves  in  fold 5 

Total 32 

After  the  blossom  buds  open,  eggs  are  deposited  within  the 
blossom  among  the  filaments  of  the  stamens  where  they  are  quite 
difficult  to  find  as  they  are  about  the  size  of  the  numerous  anthers 
of  the  stamens  and  are  concealed  by  them.  It  is  quite  probable 
that  many  more  of  the  eggs  are  laid  within  the  blossoms  than 
observations  indicate,  as  the  number  of  larvae  which  developed 
greatly  exceeded  the  number  of  eggs  actually  found. 

The  average  length  of  time  between  ovipositing  and  hatching 
of  the  egg  has  not  been  determined.  Newly  hatched  larvae  were 
found  on  material  collected  in  the  field  May  27,  or  five  days  after 
the  eggs  were  first  observed.  A  large  series  of  adults  placed  in 
breeding  cages  in  the  laboratory  failed  to  deposit  eggs.  From  ten 
adults  caged  out  of  doors,  two  eggs  were  obtained,  one  of  which 
hatched  in  seven  days  while  the  other  failed  to  develop. 

Where  the  eggs  are  laid  on  the  outside  of  buds  and  hatch  before 
the  buds  open  the  young  larvae  eat  small  holes  through  the 
surface  and  enter  the  buds  to  feed  (see  Plate  II,  b).  These  holes 
have  been  observed  where  the  eggs  had  not  been  laid  on  the  bud, 
indicating  that  the  larvae  had  traveled  a  .greater  distance  than 
the  length  of  the  bud  petiole.  The  young  larvae  have  not  been 
observed  feeding  on  the  outside  of  buds  or  on  the  leaves  where 
eggs  are  occasionally  laid;  however,  they  are  inconspicuous  and 
the  hairs  and  pubescence  of  the  raspberry  foliage  offer  such  ideal 
conditions  for  concealment  that  it  is  impossible  to  state  definitely 
without  further  investigation  that  the  larvae  do  not  feed  outside 
of  the  buds.  The  latest  date  on  which  an  egg  was  found  in  the 
field  was  on  June  29.  Full-grown  larvae  were  found  on  June  16 
and  a  few  berries  containing  larvae  were  gathered  as  late  as  July  18. 

After  leaving  the  berries  the  larvae  drop  to  the  ground  and 
enter  the  soil  forming  small  circular  cavities  or  pupal  cells  about 
three  millimeters  in  diameter.  This  fact  has  been  noted  by  Fitch 
and  Goodwin.  Fitch  also  published  a  brief  description  of  the 
pupa  which  appears  to  be  the  only  one  occurring  in  the  literature 
of  the  species.  Goodwin  failed  to  obtain  the  pupa  and  writes  as 
follows:     "A  few  of  the  larvae  formed  pupal  cells  in  the  soil  of 


PLATE  I. 


a.     Eggs,  enlarged  four  times. 


"" 

-4 
w 

7                  ^ 

f  r 

r    lip 

b.     Larva  (preserved  specimen), 
enlarged  eight  times. 


d.     Adult,  enlarged  ten  times. 


e.     Pupa,  enlarged  eight  times. 


c.     Larvae  and  injury  to  fruit,  enlarged  four  times. 
RASPBERRY  FRUIT  WORM. 


PLATE  II. 


a.  Blossom  eaten  by  beetle  at  left,  normal  blossom  at  right,  twice  natural  size. 

b.  Egg  shell  and  hole  in  bud  where  larva  entered,  enlarged  six  times. 

c.  Egg  on  leaf  petiole,  enlarged  four  times. 

d.  Three  eggs  on  bud  and  petiole,  enlarged  six  times. 

e.  Egg  on  bud  petiole,  enlarged  six  times. 


RASPBERRY  FRUIT  WORM. 


PLATE  III. 


a.     Tip  showing  injury  by  beetles,  natural  size. 


b.     Tips  with  blossom  buds  injured  by  beetles,  natural  size. 
RASPBERRY  FRUIT  WORM. 


PLATE  IV. 


a.     Injury  to  foliage  by  beetles. 


b.     Above,  raspberry  shoot  from  sprayed  plot;  67  fruits  set:    Below  shoot 
from  check  plot;  all  but  17  buds  destroyed. 

RASPBERRY  FRUIT  WORM. 


THE    RASPBERRY   FRUIT    WORM.  95 

the  breeding  jars.  These  subsequently  died  through  being  dis- 
turbed and  because  of  the  lack  of  moisture. . . .  My  observations, 
however,  substantiate  the  statement  of  Dr.  Fitch  that  they 
pupate  in  the  soil." 

Three  cages  with  soil  in  the  bottom  were  prepared  by  the  writer 
in  1922  and  full-grown  larvae  were  placed  in  each.  Two  of  the 
cages  were  placed  in  the  insectary  and  the  soil  kept  moist  but 
otherwise  undisturbed.  The  third  cage  was  examined  frequently. 
The  larvae  in  the  latter  cage  entered  the  ground  at  once  and 
within  two  days  had  formed  cells  but  failed  to  pupate  and  finally 
died.  On  October  26  the  soil  in  one  of  the  other  cages  was  ex- 
amined and  instead  of  the  pupae  being  present  as  expected,  adult 
beetles  were  found.  The  same  condition  was  found  in  the  third 
cage.  In  order  to  check  field  conditions  with  those  of  the  breeding 
cages,  a  visit  was  made  to  East  Haven  on  October  28.  The  soil 
around  the  raspberry  plants  was  examined  and  adults  were  found. 
All  of  the  beetles  obtained  were  in  the  first  one-half  inch  of  the 
top  soil.  Some  of  the  beetles  were  rather  soft  but  others  seemed 
to  be  fully  developed.  Most  of  the  beetles  were  lighter  in  color 
than  those  collected  in  spring,  but  several  were  of  normal  color. 
No  pupae  were  found  but  as  the  soil  was  moist  and  lumpy  it 
would  have  been  difficult  to  find  any  that  may  have  been  present, 
so  that  further  observations  would  be  necessary  to  determine  if 
all  of  the  adults  emerge  in  the  fall.  These  observations  differ 
from  those  of  Dr.  Fitch,  who  stated:. . .  ."in  this  situation  (pupa 
stage)  it  remains  ai  rest  through  the  winter,  and  till  the  middle 
of  May  or  a  little  later,  when  it  changes  to  its  perfect  form,  and 
is  then  a  small  beetle " 

In  1923,  fruit  infested  with  nearly  full-grown  larvae  was  placed 
in  breeding  cages  and  on  September  6,  a  number  of  the  larvae 
had  pupated.  The  last  larva  observed  in  the  material  pupated 
between  September  23  and  September  25. 

The  field  was  visited  on  October  9  and  pupae  and  one  larva 
found  in  the  soil.  No  adults  were  observed.  An  adult  emerged 
on  October  13  from  a  pupa  brought  to  the  laboratory. 

Description. 

Byturus  unicolor  Say  is  placed  in  the  family  Dermestidae  of  the 
Coleoptera.  The  members  of  this  family  occurring  in  Connecticut, 
with  the  exception  of  this  raspberry  beetle,  feed  upon  dry  animal 
and  vegetable  matter  and  include  some  of  the  well-known  house- 
hold pests  such  as  the  "larder  beetle,"  "carpet  beetle"  and  "mu- 
seum beetle."  In  Europe,  Byturus  tomentosus  Fabr.,  is  one  of  the 
most  serious  pests  of  raspberries.  It  is  closely  allied  to  B.  unicolor 
and  its  habits  are  somewhat  similar. 

The  genus  Byturus  is  readily  separated  from  the  other  genera 
of  the  family  having  "the  tarsi  with  the  second  and  third  joints 
bilobed  beneath;  front  coxal  cavities  closed  behind;  claws  armed 


96  CONNECTICUT   EXPERIMENT   STATION.  BULLETIN   251. 

with  a  large  basal  tooth"  while  in  the  other  genera  the  "tarsi  are 
simple;  front  coxal  cavities  open  behind;  tarsal  claws  simple." 
The  original  description  of  the  beetle  is  as  follows  •} 

"B.  unicolor.  Reddish  yellow,  hairy  thorax,  each  side  depressed,  tergum 
dusky,  inhabits  Arkansas,  eyes  black,  thorax  posterior  angles  broadly 
depressed  and  slightly  reflected,  the  depression  continued  on  the  side  but 
narrowed  towards  the  anterior  angles,  wings  dusky,  length  three-twentieths 
of  an  inch.  This  species  is  most  closely  allied  to  B.  tomentosus  of  the  authors. 
A  single  specimen  brought  from  Arkansas  by  Mr.  Nuttal." 

The  beetles  are  oblong-oval,  convex  above,  dull  yellow  to  pale 
brown  in  color,  rather  densely  and  coarsely  punctured  and  covered 
with  fine,  light  colored  hairs.  Head  large  with  prominent  dark, 
coarsely  granulated  eyes.  Antennae  11-jointed,  terminating  in  a 
three-jointed  club.  Thorax  wider  than  long,  slightly  broader  at 
base  than  at  apex,  sides  curved  and  with  thin,  depressed  edges. 
Elytra  about  three  times  as  long  as  wide.  Length  3.7^1.5  mm. 
Shown  on  Plate  I,  d. 

Egg.  Average  length  1.16  mm.,  width  .42  mm.  Elongate-oval, 
slightly  enlarged  towards  one  end.  Color,  nearly  white,  sometimes 
with  a  yellowish  green  tinge.  Surface  apparently  smooth,  but 
somewhat  roughened  without  definite  sculpturing  when  highly 
magnified.     Shown  on  Plate  I,  a,  Plate  II,  c,  d,  e. 

Larva.  Length  5.75  to  6  mm.,  width.  53  mm.,  nearly  cylindrical, 
tapering  towards  either  end.  Each  segment  with  sparse,  light 
colored,  stiff  hairs  arranged  in  two  transverse  rows,  those  of  the 
first  row  shorter  than  those  in  the  second.  The  ninth  abdominal 
segment  with  a  pair  of  tubercles  enlarged  at  the  base,  tapering  to 
a  point  and  -curved  towards  the  front.  The  tenth  segment  con- 
sists of  a  short,  cylindrical  blunt  proleg.  General  color  yellowish 
white,  head  amber  color  with  the  mouth  parts  darker.  There  are 
five  ocelli  appearing  as  dark  brown  spots  arranged  as  follows: 
three  in  a  vertical  row  just  back  of  the  base  of  the  antenna  and 
two  smaller  ones  back  of  and  parallel  to  the  two  upper  ocelli  in 
the  first  row.  Thoracic  shield  amber.  The  dorsal  surface  of  the 
segments  with  a  transverse  band  of  amber  to  light  brown  covering 
the  anterior  two-thirds  and  extending  about  one-third  the  way 
down  the  sides.     Shown  on  Plate  I,  b  and  c. 

Pupa.  Length  3.75  mm.,  width  1.5  mm.,  through  the  thoracic 
region,  narrowing  towards  the  end  of  the  abdomen.  Sparsely 
clothed  with  light  colored  hairs  about  .5  mm.  in  length.  Color, 
creamy  white  when  formed,  later  becoming  a  yellowish  or  amber 
color.  Eye  spots  dark  brown,  prominent.  Wing  pads  turning  a 
light  slate  color  before  the  adult  emerges.    Shown  on  Plate  I,  e. 

Control  Methods. 

The  treatment  that  has  been  recommended  against  this  insect 
is  to  spray  the  foliage  with  lead  arsenate  at  the  rate  of  four  pounds 


THE   RASPBERRY   FRUIT   WORM.  97 

(paste)  to  fifty  gallons  of  water  just  before  the  beetles  begin  to 
feed  in  spring.  Shallow  cultivation  in  the  fall  to  break  up  the 
pupal  cells  and  expose  the  pupae  has  also  been  advised. 

The  only  published  account  of  spraying  tests  against  this 
insect  that  the  writer  has  seen  is  that  of  Goodwin  in  1909.  He 
reports  that  with  one  treatment,  using  the  above  formula,  the 
injury  was  reduced  from  about  thirty-five  per  cent,  on  the  checks 
to  eight  or  nine  per  cent,  on  the  sprayed  plot. 

At  East  Haven,  lead  arsenate  at  the  rate  of  two  pounds  (dry) 
to  fifty  gallons  of  water  with  three-fourths  of  a  pound  of  calcium 
caseinate  spreader  was  used  in  comparison  with  a  dust  mixture 
containing  forty  pounds  of  sulphur,  ten  pounds  of  dry  lead  arsenate 
and  five  pounds  of  hydrated  lime.  The  block  was  divided  length- 
wise into  two  sections  and  the  north  ends  of  the  rows  of  both 
sections  were  used  as  checks.  The  applications  were  made  on 
May  12,  when  the  adults  were  appearing  in  numbers  but  before 
there  was  any  noticeable  injury  to  the  foliage.  The  field  was 
examined  on  May  16  and  it  was  found  that  the  tips  of  the  plants 
had  made  from  an  inch  to  an  inch  and  one -half  of  growth  since 
the  treatment,  and  quite  a  number  of  beetles  were  observed  on 
the  new  growth  of  the  sprayed  rows.  There  were  noticeably 
fewer  beetles  on  the  dusted  rows. 

A  second  application  was  made  on  May  19  and  examination  made 
on  May  22.  While  there  were  fewer  beetles  present  on  tbe  treated 
plots  than  on  the  16th,  there  were  still  more  on  the  sprayed  rows 
than  on  the  dusted.  No  estimate  was  made  of  the  blossom  buds 
destroyed  by  the  beetles  but  there  was  much  less  fruit  set  on  the 
check  than  on  the  other  plots.  An  examination  of  the  fruit  on 
June  29  showed  the  following  results: 

Treatment  Per  Cent.  Infested 

Dust 10. 

Spray 18 . 

Check 29.3 

These  results  are  not  entirely  satisfactory  or  conclusive  from 
the  standpoint  of  control  but  they  indicate  that  the  beetles  can 
be  poisoned  with  lead  arsenate.  The  check  plot,  located  by  request 
of  the  owner  at  the  north  end,  represented  the  minimum  infestation 
of  the  field.  As  previously  stated  the  insects  in  1921  were  more 
numerous  towards  the  south  end  where  nearly  sixty  per  cent,  of 
the  fruit  was  infested,  and  it  was  expected  that  owing  to  this 
heavy  infestation  that  the  insects  would  be  more  evenly  distributed 
throughout  the  field  in  1922.  The  dust  probably  acted  to  a  certain 
extent  as  a  repellent.  The  owner  informed  the  writer  that  an 
odor  from  the  dust  could  be  detected  for  several  evenings  after 
it  had  been  applied. 

One  reason  for  the  lack  of  control  is  undoubtedly  due  to  the 
fact  that  the  St.  Regis  is  a  rapid  growing  variety  with  the  fruit 


98  CONNECTICUT   EXPERIMENT   STATION.  BULLETIN   251. 

formed  at  the  tips  of  tiie  shoots.  In  order  to  keep  the  new  growth 
coated  it  would  be  necessary  to  make  several  and  frequent  treat- 
ments during  the  time  that  the  beetles  are  abundant. 

In  1923,  tests  were  continued  in  controlling  this  pest.  The  field 
was  divided  into  three  plo+s  as  in  1922.  The  same  spray  formula 
as  applied  in  1922  was  used.  The  dust  mixture  consisted  of 
eighty-five  pounds  of  carrier  (principally  dolomite),  fifteen  pounds 
dry  lead  arsenate  and  two  per  cent,  nicotine  sulphate. 

Four  applications  were  made  at  intervals  of  about  one  week. 
The  first  was  applied  on  May  14  as  the  adults  were  beginning  to 
appear  in  numbers  and  the  last  application  was  made  on  June  7 
as  the  first  blossom  buds  were  opening.  Later  applications  would 
have  undoubtedly  poisoned  the  bees  which  were  visiting  the 
blossoms. 

Owing  to  the  comparatively  dry  season  both  the  spray  and  the 
dust  showed  well  on  the  foliage  at  the  time  of  each  subsequent 
treatment,  but  repeated  applications  were  necessary  to  protect 
the  new  growth  as  it  developed. 

Tips  were  examined  June  16  for  injury  to  the  fruit  buds  with 
the  following  results. 

No.  of  Buds  No.  of  Buds  Per  cent. 

Treatment  Injured  not  Injured  of  Injury 

Spray 16  141  10.1 

Dust 19  140  11.9 

Check 86  47  64.6 

Fruit  from  the  different  plots  was  picked  and  examined  on 
June  30.  On  the  check  plot  there  was  only  about  twenty  per  cent, 
as  much  fruit  as  on  the  treated  plots,  Plate  IV,  b,  shows  a  shoot 
from  the  unsprayed  plot  and  one  from  the  check  plot.  Sixty-seven 
berries  had  set  on  the  former  and  only  seventeen  on  the  latter. 
The  percentage  of  wormy  fruit  was  as  follows: 

Per  cent,  of 
Treatment  Fruit  Infested 

Spray 1 

Dust 3 

Check 40 

The  combined  injury  resulting  from  destroyed  fruit  buds  and 
wormy  fruit  is  given  below: 

Per  cent,  of 
Treatment  Fruit  Destroyed 

Spray 10.99 

Dust 14.54 

Check 78.76 

Attention  is  called  to  the  fact  that  the  above  treatments  were 
not  supplemented  by  any  other  methods  of  control  which  may  be 
equally  effective  or  even  necessary  to  secure  satisfactory  results 
in  a  badly  infested  field. 


the  raspberry  fruit  worm.  99 

General  Recommendations. 

Observations  during  the  past  two  years  have  determined  that 
Byturus  unicolor  is  a  difficult  insect  to  control.  In  a  badly  infested 
field,  it  probably  would  be  necessary  to  use  every  possible  means 
to  reduce  the  number  of  beetles,  supplementing  the  spraying  or 
dusting  with  the  recommendations  indicated  below  during  the 
first  season.  The  foliage  should  be  kept  well  coated  with  lead 
arsenate  from  the  time  that  the  first  beetles  appear  until  the 
blossom  buds  open  to  such  an  extent  that  there  is  danger  of 
poisoning  bees. 

If  the  fruit  is  infested  with  the  worms  to  such  an  extent  that 
it  is  unsalable,  the  second  year's  infestation  can  be  greatly  reduced 
by  removing  and  burning  the  entire  fruit  clusters  at  about  the 
time  the  earliest  fruit  begins  to  ripen.  Observations  during  the 
past  two  seasons  indicate  that  the  eggs  have  practically  all  been 
laid  at  this  time  and  that  but  few,  if  any,  of  the  larvae  have  left 
the  fruit  to  go  into  the  ground. 

Thorough,  shallow  cultivation  as  close  as  possible  to  the  plants 
from  late  summer  to  early  fall  will  tend  to  break  up  tie  pupal 
cases  and  expose  the  pupae  to  the  elements.  The  pupae  are 
fragile  and  in  the  laboratory  cages  were  readrly  killed  by  stirring 
the  soil,  and  quickly  dried  up  when  exposed  on  the  surface.  In 
the  field  the  larvae  and  pupae  have  only  been  observed  in  the 
upper  three-fourths  of  an  inch  of  the  soil. 

During  the  present  fall,  poultry  had  had  the  run  of  the  East 
Haven  field  and  it  was  difficult  to  find  larvae  and  pupae  in  the 
soil  under  the  plants  even  in  the  check  plot.  Where  raspberries 
are  grown  for  home  use  only,  the"  patch  could  often  be  located  so 
that  poultry  could  be  turned  into  it  during  the  time  that  the 
larvae  and  pupae  are  in  the  soil. 

Literature. 

1  Say,  Thomas  (original  description).  Journal  of  the  Academy  of  Natural 
Sciences  of  Philadelphia,  Vol  3,  page  197,  1823;  Complete  Writings,  Vol  2, 
page  126,  1869. 

2  Packard,  A.  S.    Guide  to  Study  of  Insects,  page  448,  1869. 

3  Fitch,  Asa.  Transactions  N.  Y.  State  Agricultural  Society,  Vol.  30,  pages 
358-360,  1870-1872. 

■*  Saunders,  William.  Report  Entomological  Society  of  Ontario  for  1873, 
page  10,  1874. 

6  Fletcher,  James.  Central  Experimental  Farm  (Canada),  Report  of  Ento- 
mologist and  Botanist  for  1887,  page  31. 

6  Lintner,  J.  A.    Insects  of  New  York,  8th  Report,  page  298,  1893. 

7  Goodwin,  W.  H.    Ohio  Agr.  Expt.  Station,  Bulletin  209,  1909. 
8Leng,  C.  W.    Catalogue  of  the  Coleoptera  of  America  North  of  Mexico, 

page  189,  1920. 

9  Felt,  E.  P.  35th  Report  of  the  State  Entomologist  of  New  York  for  1921, 
page  40,  1923. 


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